#include<stdio.h>
#include<unistd.h>
#include<string.h>
int main(int argc, char* argv[]){
  if(argc == 2){
    if(strcmp("-a", argv[1]) == 0){
      printf("This is function 1\n");
    }
    else if(strcmp("-b", argv[1]) == 0){
      printf("This is function 2\n");
    }
    else if(strcmp("-c", argv[1]) == 0){
      printf("This is function 3\n");
    }
    else{
     printf("please use ./CMD_LINE_ARG [-a or -b or -c]\n");
    }

  }
  else{
     printf("please use ./CMD_LINE_ARG [-a or -b or -c]\n");
  }



//  for(int i = 0; i < argc; ++i){
//    printf("argv[%d] : %s\n", i, argv[i]);
//  }
  return 0;
}
